Wood-derived Co@CoO/BNC bifunctional electrocatalyst for high-efficient zinc-air batteries

• Wood-derived Co@CoO/BNC as the catalytic electrode in Zn-air battery was rationally designed. • Highly bifunctional catalytic activities toward ORR and OER were achieved on the Co@CoO/BNC. • Zn-air battery exhibits high specific capacity and outstanding stability using Co@CoO/BNC as air electrode. The utilization of wood-derived porous carbon as catalytic electrodes in metal-air batteries has garnered significant attention. Although extensive efforts have focused on developing and optimizing active sites, the insufficient electrical conductivity of wood-derived carbon-based electrodes remains a frequently overlooked challenge. In this study, we successfully constructed boron and nitrogen co-doped Co@CoO/BNC composite through multidimensional structural and compositional synergy, demonstrating exceptional catalytic activity. Specifically, ZIF-67 was confined in situ within wood cell structure to derive carbon materials with controllable growth of Co@CoO nanoparticles, preserving the hierarchical porous structure to ensure superior mass and electron transport. Furthermore, boron and nitrogen co-doping generated B-N-C, which modulated the electronic structure of metal centers and induced high-density topological defects in the carbon matrix, synergistically enhancing catalytic activity. The Co@CoO/BNC composite demonstrated outstanding bifunctional catalytic performance for both oxygen reduction reaction (ORR, half-wave potential E 1/2 = 850 mV) and oxygen evolution reaction (OER, overpotential of 310 mV at 10 mA cm −2 ). Notably, the narrow potential gap of 715 mV between ORR and OER significantly surpassed that of commercial Pt/C + RuO catalysts. Moreover, the as-prepared Co@CoO/BNC architecture also exhibited remarkable stability. When employed as an air cathode in zinc-air batteries, it delivered a specific capacity of 958.5 mA h g −1 and maintained exceptional cycling stability for over 300 hours. This work provides critical insights into the rational design of carbon-based bifunctional oxygen electrocatalysts and highlights the high-value utilization of forest biomass-derived materials in renewable electrochemical energy conversion systems.